I own a pair of paradigm v.2 reference floorstander loudspeaker and i have a problem with it.

When i crank up the volume to a certain level the mid range starts to jarr,like it's bottiming out.I thought the bass was too high so i connected another pair of paradigm studio v.2 and its sounds perfect with the same volume.

Can someone please help me figure out this problem since the floorstander should be able to take up more volume than the studio.
picture of the speaker below